As discussed in PR review, there may be an off-chance that the index
returned doesn't match up with SDL's display indexing.
This change ensures that the indices match and adds a safety check for
off-screen windows.
With the introduction of this function, it is possible that for certain
monitor and window configurations, creating an SDL window will cause a
native crash.
```
Crashed Thread: 0 Dispatch queue: com.apple.main-thread
Exception Type: EXC_BAD_ACCESS (SIGSEGV)
Exception Codes: KERN_INVALID_ADDRESS at 0x0000000000000050
Exception Codes: 0x0000000000000001, 0x0000000000000050
Exception Note: EXC_CORPSE_NOTIFY
Termination Reason: Namespace SIGNAL, Code 11 Segmentation fault: 11
Terminating Process: exc handler [56627]
VM Region Info: 0x50 is not in any region. Bytes before following region: 140737486737328
REGION TYPE START - END [ VSIZE] PRT/MAX SHRMOD REGION DETAIL
UNUSED SPACE AT START
--->
VM_ALLOCATE 7fffffe75000-7fffffe76000 [ 4K] r-x/r-x SM=ALI
Thread 0 Crashed:: Dispatch queue: com.apple.main-thread
0 libSDL2.dylib 0x10247f665 SDL_UpdateFullscreenMode + 357
1 libSDL2.dylib 0x10247ec70 SDL_CreateWindow_REAL + 1504
2 ??? 0x111262de8 ???
3 ??? 0x110c39fff ???
4 libcoreclr.dylib 0x101fdf2a9 CallDescrWorkerInternal + 124
```
Tracking thread from our end: https://github.com/ppy/osu-framework/issues/5190
Regressed with: https://github.com/libsdl-org/SDL/pull/5573
In testing, the window would not find a valid screen if created
"hanging" off a primary display with a secondary display below it. In
checking why this was the case, the `display_centre` was being
calculated with a negative y origin, causing a final negative value
falling outside all display bounds:
```
SDL error log [debug]: display_centre.y = -1296 + 1296 / 2
SDL error log [debug]: Display rect 0: 0 0 2560 1440
SDL error log [debug]: Display rect 1: 2560 -625 1080 2560
SDL error log [debug]: Display rect 2: 0 1440 1728 1296
```
The method that was being used to find the current window using the frame
origin/size seems unreliable, so I have opted to replace it with with a
tried method (https://stackoverflow.com/a/40891902).
Initial testing shows that this works with non-standard DPI screens, but
further testing would be appreciated (cc @sezero / @misl6 from the
original PR thread).
We actually request CSD mode with xdg-decoration for borderless
windows, so we get what we wanted there and there's no point in going
into fallback paths.
Extend the SDL_WINDOW_ALLOW_HIGHDPI flag documentation to stress the importance of querying the window drawable size after every window event to avoid rendering issues in a mixed-DPI environment.
check_include_path is not meant to be used to check for presence of a
library. This is because a BOOL is cached.
Avoid this caching by using find_file.
`find_file` caches a patch instead of a bool and will always run when
the result failed.
The 5.1 versions didn't use the new algorithm, and making that new
algorithm work took so many permutes that it was significantly slower
than just using the scalar versions.
However, mono-to-stereo is an extremely common conversion, and it's
trivial to accelerate it with plain SSE, so that was added!
Currently, the SDL_WINDOWEVENT_RESIZED event is sent before the actual
window is resized (and various internal state, such as the desired
GL/Vulkan backbuffer size, are updated). This makes sense, as SDL will
discard a no-op resize, which would be the case if we had resized before
sending the event (indeed, there are existing hacks to prevent this).
However, this means that SDL_{GL,Vulkan}_GetDrawableSize() will still
use the old size in the SDL_WINDOWEVENT_RESIZED handler. In the case of
SDL_Renderer, this means the drawable size it uses will be wrong, and
the viewport will get "updated" to the old value.
This then results in bug #5899.
Sam Lantinga
Dean Herbert
Sebastian Krzyszkowiak
Anonymous Maarten
Ozkan Sezer
slime
Frank Praznik
Ivan Epifanov
Ethan Lee
Ryan C. Gordon
David Gow